Convert between bytes, kilobytes, megabytes, gigabytes, terabytes, petabytes, bits and binary units (KiB, MiB, GiB, TiB). Click any row in the conversion table to set it as the target unit.
All Data Storage Units — Click a row to select as target
Unit
Name
Value
About Data Storage Units
Data storage is measured in bytes (8 bits each) and their multiples. Two competing systems exist: the SI decimal system used by storage manufacturers (where 1 KB = 1,000 bytes), and the binary system used by operating systems (where 1 KiB = 1,024 bytes). This discrepancy is why a "1 TB" hard drive shows as 931 GB in Windows — the drive manufacturer uses decimal; Windows reports in binary. Understanding both systems is essential for anyone working with computers, networking or storage.
📦 Decimal Units (SI) — Storage Manufacturers
The SI decimal system defines: 1 KB = 1,000 bytes, 1 MB = 1,000,000 bytes, 1 GB = 1,000,000,000 bytes, 1 TB = 1,000,000,000,000 bytes. Hard drives, SSDs, flash drives and cloud storage providers all use this system when advertising capacity. It produces the larger, more impressive numbers used in marketing.
💻 Binary Units (IEC) — Operating Systems
The IEC binary system uses powers of 2: 1 KiB = 1,024 bytes, 1 MiB = 1,048,576 bytes, 1 GiB = 1,073,741,824 bytes, 1 TiB = 1,099,511,627,776 bytes. Windows traditionally reports file sizes in binary units (calling them GB/MB, confusingly). macOS switched to decimal reporting in 2009. Linux typically uses binary units. The difference grows with scale — a 1 TiB file is 1.1 TB in decimal.
Why your 1 TB drive shows as 931 GB in Windows: The drive contains exactly 1,000,000,000,000 bytes (1 decimal TB). Windows divides by 1,073,741,824 (1 GiB) instead of 1,000,000,000 (1 GB) to display the size, giving 931. This isn't data loss — it's a unit mismatch. macOS and modern Linux show the correct 1 TB (using the decimal definition Windows confusingly calls GB).
Powers of 2 — Binary Reference Table
Binary prefixes (powers of 2) used in computing differ from SI decimal prefixes.
Frequently Asked Questions — Data Storage Converter
In the decimal system (SI), 1 kilobyte (KB) = 1,000 bytes. In the binary system (IEC), 1 kibibyte (KiB) = 1,024 bytes. Hard drive manufacturers use KB = 1,000; operating systems traditionally report in KiB = 1,024 (often calling it "KB"). This is why a "1 GB" file on a manufacturer's website appears slightly smaller in Windows.
One terabyte (TB) = 1,000 gigabytes (GB) in the decimal system. In binary, 1 tebibyte (TiB) = 1,024 gibibytes (GiB). A "1 TB" hard drive has 1,000,000,000,000 bytes (decimal), which Windows shows as approximately 931 GiB (because Windows divides by 1,073,741,824 instead of 1,000,000,000).
A gigabyte (GB) = 1,000,000,000 bytes (10⁹, decimal). A gibibyte (GiB) = 1,073,741,824 bytes (2³⁰, binary). The difference is about 7.4%. Hard drive manufacturers label drives in GB (decimal). Windows reports in GiB but labels them GB (confusingly showing the drive as smaller than advertised). macOS reports in decimal GB correctly since 2009.
A typical smartphone JPEG photo is 3–8 MB depending on resolution (12–48 MP) and compression settings. HEIC photos (iPhone) are approximately 2–5 MB at the same quality. RAW photos from DSLRs are typically 20–50 MB per file. A 12 MP smartphone shot at moderate compression is usually around 4–6 MB.
A 4K movie typically requires 50–100 GB for Blu-ray quality. 4K streaming (Netflix, Amazon) uses 7–15 GB/hour with H.265 compression. A 2-hour 4K Netflix stream uses approximately 14–30 GB. Downloading a 4K movie from Apple or Google at higher quality can be 50–80 GB per film.
Mbps = megabits per second (used for network speeds, ISP broadband). MB/s = megabytes per second (used for file transfer and storage speeds). Since 1 byte = 8 bits, divide Mbps by 8 to get MB/s. A 100 Mbps internet connection transfers approximately 12.5 MB/s. A 1 Gbps (1,000 Mbps) connection transfers 125 MB/s. ISPs advertise in Mbps (larger number); storage devices are rated in MB/s.
1 byte = 8 bits. This is the fundamental relationship in computing. All larger units follow: 1 KB = 8 Kbits, 1 MB = 8 Mbit, 1 GB = 8 Gbit, 1 TB = 8 Tbit. Network speeds are measured in bits (Mbps, Gbps); storage capacity is measured in bytes (MB, GB, TB). To convert network speed to file transfer speed: divide Mbps by 8 to get MB/s.